1. Field of the Invention
The present invention relates to an image processing apparatus and a control method thereof that can treat paper fingerprint (hereinafter, also called paper print) information.
2. Description of the Related Art
A paper is made of plant fibers with a diameter of about 20 to 30 microns entangled with each other. Random patterns are formed by the entanglement and these random patterns are different from one another sheet by sheet as same as fingerprints. Such a random pattern on the paper is called paper fingerprint information.
Since the paper fingerprint information is different sheet by sheet, if it is registered that “the original I issued is a paper having this paper fingerprint information”, it is convenient afterward to discriminate between the “original” and a “counterfeit”. Note that “a copy of the original” is naturally included in the counterfeits.
Japanese Patent Laid-Open No. 2004-214831 discloses a technique in which a region for paper fingerprint information acquisition is set to be a region apart by a predetermined distance from a reference position with a mark added to a paper to be an original as the reference position when the original is made. This patent document also discloses acquisition of the paper fingerprint information from a region set for paper fingerprint information acquisition. Further, this patent document discloses a technique for encoding the acquired paper fingerprint information to generate an encoded image and printing the generated encoded image on a paper to be the original.
Also, in the print-on-demand print industry, there is used a method to print document data on one sheet by a lay out (also called imposition) of multiple pages for a purpose of saving the number of output sheets. A final product is obtained by cutting the printed sheets with a cutter or the like. FIGS. 20 and 21 show an example of the printing method. In the description hereinafter, a printed material after the cutting is denoted by a final product. Symbol 1401 and Symbol 1402 show a sheet and a document data of one page, respectively. On the one sheet 1401 shown in FIG. 20 is laid out ten pages of the documents (ten pieces of the one page document data 1402). Marks 1403 shown in FIG. 20 for cutting are called register marks. FIG. 21 shows an example a diagram focused on one page document data. The final product is an area 1404 cut at the marks (register marks) 1403. Such a printing method is called multi-frame printing or multi-page printing, and a document data layout method used in such a printing method is called a multi-up imposition or multi imposition.
However, there are problems as follows, when the paper fingerprint technique and the multi-page printing are applied at the same time.
FIGS. 22 and 23 are examples of diagrams showing the problems.
First, the problem shown in FIG. 22 will be described. In FIG. 22, a sheet 1501 shows a multi-page imposition of one page document data areas 1502. A conventional paper fingerprint registration is processing performed for a sheet. That is, the paper fingerprint registration is carried out for the sheet 1501 shown in FIG. 22. Accordingly, the paper fingerprint to be registered is located at a random position 1503 as shown in FIG. 22 and the number of the paper fingerprints becomes also random. When a final product 1504 is obtained after cutting of this sheet 1501 as shown in FIG. 22, the final product may not include the registered paper fingerprint information as shown in the drawing and various processing such as original guarantee by the paper fingerprint information may become ineffective.
Next, another problem will be described with reference to FIG. 23. For solving the above problem, it can be devised that the paper fingerprint registration is carried out after preliminary cutting of the sheet 1501. However, this method becomes a very time-consuming process because the paper fingerprint registration needs to be carried out for each of the final products 1504. In an example shown in FIG. 23, ten times of reading processing in total by setting the 10 final products 1504 in a finger print reading apparatus continuously is necessary for carrying out the paper fingerprint registration for one sheet 1501.